Acyl derivative of para-aminophenylarsinic acid.



UNITED STATE PaTENT oFFioE.

PAUL EHRLIGH AND ALFRED BERTHEIM, OF FRANKFORT-ON-THE-MAIN, GERMANY,

ASSIGNORS TO FARBWERKE VORM. MEISTER LUCIUS & BRUNING, OF HOGHST-ON- THE-MAIN, GERMANY, A CORPORATION OF GERMANY.

AGYL DERIVATIVE OF.PARA-AMINOPI-IENYLARSINIO ACID.

Specification of Letters Patent.

Patented Dec. 15, 1908.

Application filed October 3, 1907. Serial No. 395,673. I

To all whom it may concern:

Be it known that we, PAUL EHRLICH, M. D., LL. 1)., Chicago, professor of medicine, and ALFRED BERTIIEIM, Ph. 1)., both citizens .of the Empire of Germany, and" re;

siding, at Frankfort-on-the-Main, Germany, have invented certain new and useful Improvements in Acyl Derivatives of Parai liminophenylarsinic Acid, of which the following is a specification.

We have found that acid radicals may be introduced into para-aminophenlyarsinic acid by boiling the latter with acids. The reaction involved may, for instance, be illustrated by the following equation:

The resulting acid derivatives of para-amii'iophenylarsinic acid are valuable as mediof para-aminophenylarsinic. acid are boiled with 150 ccm. of glacial acetic acid with'return tlow until a test with a, solutionof paradimethylamidobenzaldehyde in dilute hydrochloric acid gives only a very weak yellow coloration. Hereupon about of the acid is distilled off and the residue is treated with water, the ac-etyl-para-amidophenyl-arsinic acid being then precipitated. It is readily soluble in soda, soluble with difficulty in dilute hydrochloric acid and is saponified by boiling with concentrated hydrochloric acid forming para-aminophenlyarsinic acid.

As stated by Dr. Browning (Chemo-Therapy in Trypanosome Infections: An Experi mental Study, The Journal of Pathology and Bacteriology, Vol. XII, 1908), the effect of atoxyl on experimental trypanosome infections is'not favorable. But when using the sodium-salt of acetyl-para-aminophenylarsinic acid (acet-atoxyl) and injecting 0.033 of it into mice weighing-20 gr.

which have been infected with trypanosomes a complete recovery is attained. Of the acetylatoxyl 0.033 gr. may thus be injected.

into mice infected with trypanosomes, whereas if 0.005 gr. of atoxyl be injected into such an animal, it will have a fatal effect on the same. The sodium-salt of the acetyl-parae amzinophenylarsinic acid is also used in the treatment-of syphilis in such a manner that repeated injections of 0.6 gr. of it are made, as has been indicated by Professor Neisser in his report submitted to the Congress of Dermatologists, held at Frankfort on the Main on the 9th June, 1908.

Having now described our invention, what we claim is 4 1. As products, the acyl derivatives of para-aminophenylarsinic' acid, the composition of which corresponds to the formula: Acyl-NHC H,AsO(OH) being white crystalline compounds, soluble with diiiiculty in water, alcohol and ether, readily soluble in alkali and alkali-carbonates with formation of alkali salts, re-precipitated from these solutions by hydrochloric acid and yielding, when heated with concentrated hydrochloric acid, para-aminophenylarsinic acid.

2. As product, acetyl-para-aminophenylarsinic acid, being a white compound of the crystallizing from acetic acid in leaflets, solublc with difficulty in water, alcohol and ether, readily soluble in-a sodium carbonate solution to a sodium salt from which solution it is precipitated unchanged by means of hydrochloric acid, but yielding, when boiled with concentrated hydrochloric acid, para-aminophenylarsinic acid.

In testimony, that weclaim the foregoing composition of CH CONHC,H,AsO(OH) I 

